Structure determination of thin polymer films using GIXRD and AFM Both atomic force microscopy (AFM) and grazing incidence x-ray diffraction (GIXRD) are used to determine the structure of polymer thin films. To enable experiments using these techniques to be conducted experimental apparatus was designed and built. These apparatus' included an in-situ heater to allow investigations at elevated temperatures to be conducted as well as a chamber for the work conducted using GIXRD to minimise the background scattering incident on the detector. The structure of two polymers, F8 and PQT-12, have been investigated using GIXRD. Both of these polymers align in a layered geometry normal to the surface, and in an isotropic polycrystalline ordering in the plane of the surface. The F8 polymer, while in the a-crystalline phase, has a unit cell dimension of 27.3 0.3A normal to the surface and unit cell dimensions of 24.3 0.3A and 17.1 0.2A in the plane of the surface. As- spun PQT-12 of molecular weight of 5000amu has been found to form a metastable self- assembled crystalline phase with unit cell dimensions of 35.6 0.7A out-of-plane and 13.10 0.12A, 16.4 0.6A in-plane. The structure of PQT-12 has been shown to be dependent on molecular weight, annealing and physical preparation of the substrate. The rate and mechanisms of crystallisation of a third polymer, PET, have also been investigated as a function of anneal temperature. The crystallisation was followed at each given temperature to follow the growth of individual spherulites. As the thickness of the PET film was increased from 43nm to 120 nm the radial growth rate of the spherulites increased linearly from 8.0 0.9nm/min to 14.3 1.3nm/min.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:585005 |
| Date | January 2010 |
| Creators | Thomas, Huw E. |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/55063/ |
Page generated in 0.0016 seconds